I think the Sunsmiles variety may work well. It's worth trying. The Japanese strive to use Ipomoea nil strains that have been selected for large flower size. I think Sunsmiles may lack in giant sized flowers but its variegated foliage I've always found attractive. In order to get those large flowers there is a specific regimen of fertilizer applications, when to begin feeding, and at what concentration, when to cut the vine and where, and it's all done on a strict calendar schedule to make them open on the day of a morning glory festival or competition. There are certain methods that have been developed by asagao clubs in Japan that yield different presentations of leaves and numbers of flowers. For example, the Kyoto Method will yield a plant that will have as many as 18 flowers open at one time. The Nagoya Method will make a smaller plant with at most 2 flowers. I am doing a method which is a modification of Nagoya Method I suppose. I am still a student, and have no specific knowledge of the various schedules of production because the language is all in Japanese. I'll get there eventually, I hope, before too long.